Workstation Environments

with Nix and home-manager

dustin.lacewell@workiva.com

Worked at Docker Inc
Helped establish and grow DockerHub CI/CD
Moved from San Francisco, from Chicagoland
Obsessed with Developer UX/QoL

Workstation Environments?

Software used for work (editors, tools, utilities, etc)

Associated configuration

Ideal Properties

Declarative
Version controlled
Reproducable
Extensible

Nix

...a powerful package manager for Linux and other Unix systems that makes package management reliable and reproducible.

It provides atomic upgrades and rollbacks, side-by-side installation of multiple versions of a package, multi-user package management and easy setup of build environments.

"The Purely Functional Package Manager"

Nixlang

Nix

NixOS

NixOps

Disnix

Hydra

Purity

Atomicity

Laziness

Reproducibility

Nix is a package manager

Manages packages...! 😮
Everything is isolated under /nix
Every package lives in /nix/store

Nixpkgs

Around 6500 packages for Linux and OSX

"On GNU/Linux, the packages in Nixpkgs are ‘pure’, meaning that they have no dependencies on packages outside of the Nix store. This means that they should work on pretty much any GNU/Linux distribution."

Bread and Butter

#> nix-channel --add https://nixos.org/channels/nixpkgs-unstable

#> nix-env -qa 'firefox.*'

#> nix-channel --update

#> nix-env -i firefox

#> nix-env -e firefox




stdenv.mkDerivation rec {
  name = "hello-2.10";

  src = fetchurl {
    url    = "https://ftp.gnu.org/gnu/hello/hello-2.10.tar.gz";
    sha256 = "1im1gglfm4k10bh4mdaqzmx3lm3kivnsmxrvl6vyvmfqqzljq75l";
  };

  meta = {
    description = "A program that produces a familiar, friendly greeting";
    platforms = stdenv.lib.platforms.all;
  };
}

Package Purity

Nixlang's purity -> Nix's reproducibility

/nix/store/r8vvq9kq18pz08v249h8my6r9vs7s0n3-firefox-8.0.1

/nix/store/y15i77ghwd0w0xcw8hl2cl1gs4fi9dj5-firefox-8.0.1

Text

SYMLINKS

SYMLINKS EVERYWHERE

Dependencies are symlinks
Profiles contain symlinks
Profiles are symlinks

Atomic upgrades and rollback

#> nix-env --upgrade firefox

#> nix-env --rollback

Nix is a language

Functional
(Mostly) Pure
Lazy / Non-strict evaluation
A "modeling" language

It has basic data types

Integers (no floats): 5 + 5
Strings: "hello world"
Lists: [ "blah" name 5 ]
Attrsets: { foo = "bar"; biz.baz = "boz"; }

Every file is an expression

# example.nix
{
  foo = "bar";
  biz = [ 1 "two" 3 ];
}

let expressions are nice

# let <names> in <expr>
let
  filename = "config.conf";
  prefix = "/etc/foo";
  path = "${prefix}/${filename}"
{
  file = touchFile path;
}

Functions

# { <args> }: <expr>
let
  func = { prefix, filename ? "foo.conf" }: {
    fullPath = "${prefix}/${filename}";
    ready = false;
  };
in func { prefix = "/etc/foo"; }

Files can be imported

# prefix.nix
{ filename, prefix ? "/etc/foo" }: 
  "${prefix}/${filename}"

# foo.nix
let
  prefix = import ./prefix.nix;
in {
  fooFile = prefix { filename = "foo.conf"; };
}
# {fooFile="/etc/foo/foo.conf";}

Anatomy of a Package

Depend on other packages
Built from some source
Files are written to $out
Basically a special attrset

with import <nixpkgs> {};

stdenv.mkDerivation {
  name = "hello-2.1.1";

  src = fetchurl {
    url = http://nix.cs.uu.nl/dist/tarballs/hello-2.1.1.tar.gz;
    md5 = "70c9ccf9fac07f762c24f2df2290784d";
  };

  buildInputs = [ tar ];
  builder = builtins.toFile "builder.sh" "
    source $stdenv/setup
    tar xvfz $src
    cd hello-*
    ./configure --prefix=$out
    make
    make install
  ";
}

with import <nixpkgs> {};

stdenv.mkDerivation {
  name = "hello-2.1.1";
  src = fetchurl {
    url = http://nix.cs.uu.nl/dist/tarballs/hello-2.1.1.tar.gz;
    md5 = "70c9ccf9fac07f762c24f2df2290784d";
  };
}

stdenv.mkDerivation {
  name = "foo-5.4";
  buildPhases = [ "buildPhase" 
                  "installPhase" ];
  buildPhase = ''
    gcc foo.c -o foo
  '';
  installPhase = ''
    mkdir -p $out/bin
    cp foo $out/bin
  '';
}

Packaging Harbour-CLI

Golang CLI utility
Uses 'Glide' for dependencies
Produces a single binary

Use a profile?

#> nix-env --switch-profile /nix/var/nix/profiles/harbour-cli

#> nix-env -i go glide git emacs

#> emacs main.go

#> go build, etc

# default.nix

with import <nixpkgs> {};

stdenv.mkDerivation {
  name = "harbour-cli";
  src = ./.;
  buildInputs = [ git go glide ];
}

nix-shell

#> nix-shell

#> which go

/nix/store/2r298x93l2v48yrjp31381vcghyrnlz3-go-1.9.2/bin/go

#> emacs main.go

#> glide install && go build, etc

# default.nix

with import <nixpkgs> {};

stdenv.mkDerivation {
  name = "harbour-cli";
  src = ./.;
  buildInputs = [ git go glide ];
  buildPhases = [ "unpackPhase" "buildPhase" ];
  builderPhase = ''
    glide install
    go test --cover
    go build -o $out/bin/harbour-cli
  '';
}

Installing the package

#> nix-env -i -f .

#> which harbour-cli

/Users/dustinlacewell/.nix-profile/bin/harbour-cli

#> nix-env -i \

https://github.com/Workiva/harbour-cli/archive/master.tar.gz

NixOS

Young, typical GNU/Linux distro
Built on top of Nix
Declarative system configuration

nix-rebuild

Young, typical GNU/Linux distro
Built on top of Nix
Declarative system configuration

Configuration.nix

Young, typical GNU/Linux distro
Built on top of Nix
Declarative system configuration

Syntax Sugar

Young, typical GNU/Linux distro
Built on top of Nix
Declarative system configuration

Repetition Blues

Young, typical GNU/Linux distro
Built on top of Nix
Declarative system configuration

Set Extension

Young, typical GNU/Linux distro
Built on top of Nix
Declarative system configuration

Functions

Young, typical GNU/Linux distro
Built on top of Nix
Declarative system configuration

Higher-order Functions

Young, typical GNU/Linux distro
Built on top of Nix
Declarative system configuration

Modularity

Young, typical GNU/Linux distro
Built on top of Nix
Declarative system configuration

Functions

Young, typical GNU/Linux distro
Built on top of Nix
Declarative system configuration

Configuration Modules

Young, typical GNU/Linux distro
Built on top of Nix
Declarative system configuration